Acoustic telephone



(No Model.)

J. S. DAVIS. Acoustic Telephones.

No. 233,215. Patented Oct. 12,1880.

IN-VENTORI WITNESSES UNITED STATES PATENT @FFICE.

JOHN S. DAVIS, OF ATILEBOROUGH, MASSACHUSETTS.

AoousTic TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 233,215, dated October 12, 1880.

Application filed April 8, 1880.

To all whom rt may concern:

Be it known that I, JOHN S. DAVIS, of Attleborough,in the county of Bristol and State of Massachusetts, have invented a new and useful Improvement in Acoustic Telephones; and I hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming part of this specification.

This invention has reference to animprovement in that class of telephones in which a diaphragm is vibrated by the voice, and the vibration transmitted by means of a wire connected with the diaphragm, and also to another diaphragm, and the vibrations reproduced, so that conversation can be carried on between two points.

The object of this invention is to improve the construction and utility of such a role phone-line.

Theinvcntion consistsin the peculiar method of suspending and securing the wire; also, in the peculiar construction and arrangement of the sound producing and receiving device, and also in the peculiar construction and arrangement of a call for an acoustic telephone, as

will be more fully set forth hereinafter.

Figure l is a view of the transmitting and receiving instrument, showing also a pivoted call, which can be swung over the aperture in the transmitter. Fig. 2 is a sectional view of the transmitting and receiving instrument, showing the sheet-metal diaphragm and the connecting-wire, also the reed-call. Fig. 3 is a perspective View, showing the line-wire, the manner of supporting the same, as also the manner of connecting the receiving and transmitting instrument with the linewire. Fig. 4 is an enlarged view, illustrating a preferred mode of supporting the line-wires.

In the drawings, a represents acircular disk, having on its face a concaved or dished depression, a, in the center of which is the circular opening a 1) is a circular disk, also provided with a central hole.

Both the disks wand 11 have a narrow edge at their periphery-level, so as to form a hearing for the diaphragm c, and the rest of the inner faces next the diaphragm are beveled to the central holes, as is shown in Fig. 2.

The diaphragm 0 isa circular disk of sheet (No model.)

metal, and I prefer for this a sheet of soft brass, as it will produce a fuller note than harder metal and avoids the creaking noise incidental to hard-mctal disks.

(1 is a button, to which the wire 0 is connected so as to bear with its rounded side against the diaphragm by reason of a slight strain on the wire 6, which is connected with the line-wire f, as shown in Figs. 2 and 5, between two fastenings. By securing the wire 6 to the wire f any desired tension can be read ily secured not affected by the strain on the line-wire or by action of wind on the same.

9 is a reed-call pivotally connected, so that it may be quickly placed over the central aperture, and the vibration of the reed in the call will produce a strong vibration of the diaphragm, so that the reproducing-diaphragm on the other end of the line will give a loud call, which can be heard a great distance, and is so dilfereut from ordinary sounds that the attention is at once directed to the same.

The line-wire f may extend a long distance, and be supported at intermediate points by means of supports such as are shown in Fig. at. Such a wire requires strong connections on the ends, and when such ends are direct-1y connected with the diaphragm of an acoustic telephone the strain prevents the free vibrations of the diaphragm.

To avoid this difiiculty I firmly secure the ends ofthe wire beyond thepoint at which thetransmitteris placed. I now secure the wire 6 connected with the diaphragm to the wire f, and spring said wirefslightly, so that the spring of the diaphragm will be sufficient to regain its natural plane, and a slight eit'ort of the voicesuch as a whisper-will communicate the vibrations to the wire, to be reproduced at the other end. By this arrangement more than two transmitting and receiving instruments may be placed 011 one line of wire.

To transmit the vibrations clearly and fully I suspend the wire by means of a fibrous cord, 75, from any support, t. I prefer a slightlytwisted hempen cord, but other fibrous material may be used.

Z is a union-piece of metal, to which the ends of the wire are connected, and to which the cord is also connected, as shown in Fig. 4. It may be made of light sheet or cast metal,

or it may be formed of a piece of wire; but the connection of the two wires ff with the piece l must be such as will not interfere with the vibrations of the wire.

The disks a and b, forming the transmitting and receiving instrument, I prefer to make of some light resonant wood. The diaphragm c bears on the outer edge, and the two disks are secured together with the diaphragm between them by means of nails or screws. The beveled inner faces of the disks to and I) allow the diaphragm to vibrate at the center, and the beveled surfaces allow the air impelled against the diaphragm 0 to act by repulsion on alarger part of the diaphragm, and I find that with such beveled surfaces the enunciation of speech is more fully reproduced, giving a fuller note and clearerreproduction of the timbre of the voice.

Myimproved acoustic telephone can be used forconsiderabledistances and can be branched off to more than the two points at each end of the line. Then a call is made by the reed and answered the reed is swung on one side, and conversation can be held between distant points by standing before the transmitter and speaking toward the opening a Any answer can be distinctly heard without placing the car near the transmitter, and neither battery nor magnets are used, the whole being cheap and simple in construction.

Having thus described my invention, I claim as new and desire to secure by Letters Patent 1. In a telephone, the combination, with the transmitter or receiver, of a reed secured to a pivoted arm and adapted to be swung into line with said instrument, so that such reed shall be supported independently of said instrument and out of contact therewith, but in alignment with its opening, substantially as described.

2. In an acoustic telephone, the method of securing the line-wire, the same consisting in securing the ends of the wire, as described, suspending the Wire by means of fibrous material, and connecting the diaphragms to the line-wire by means of the wire 0, as described.

3. In an acoustic telephone, the combination, in the transmitting and receiving instruments, of the disk a, concaved at a, havinga central opening, a", and a flattened rim dished inwardly toward the central opening, and a disk, I), having a central opening and a flattened rim dished inwardly toward the central opening, a soft-metal diaphragm secured between said flattened rims of said disks, the button d, and the attached wire e, secured to the main or line wire f at a point between the point of attach ment of said line-wire below the instrument and its point of suspension above such instrument, all constructed and arranged to operate substantially as described and shown.

JOHN S. DAVIS.

Witnesses:

J OSEPH A. MILLER, JosEPH A. MILLER, Jr. 

